multimeter

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  <a href="https://mmt.dev">
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  <h4>Git-native REST client and API tests in VS Code. YAML .mmt files in Git.</h4>

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    <a href="https://www.npmjs.com/package/mmt-testlight">CLI</a>
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    <a href="https://mmt.dev/docs/quick-start">Docs</a>
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<p align="center">
  <img src="res/intro.png" alt="Multimeter — Get Started, YAML, and API tester" width="640" />
</p>

## 🚀 Start with a request. Grow into a platform.

**Multimeter** is Git-native API testing in VS Code. Requests, tests, mocks, and docs are YAML `.mmt` files in your repo.

Start with a single HTTP request.

Grow into tests, suites, mocks, reports, documentation, and CI when you need them.

All in the same tool. No migration. No second product.

## 🎯 What you get

**Simple by default**

- ✅ Git-native, file-based YAML
- ✅ Lightweight — no account, no cloud lock-in
- ✅ Collaboration through pull requests, like code
- ✅ The same files locally and in CI

**A full testing platform when you need it**

- ✅ HTTP, WebSocket, GraphQL, and gRPC
- ✅ Multi-step flows and test suites
- ✅ Mock servers
- ✅ Generated documentation
- ✅ Reports
- ✅ CI with `testlight`

**AI in the same files**

- ✅ Generate tests from an API or a description (Cursor, Copilot, Claude via MCP)
- ✅ Judge replies — semantic similarity, or open-ended checks like how funny a response is
- ✅ Bring your own model (Ollama or cloud)

[See all features →](https://mmt.dev/#features)


## ⚡ Start simple

Multimeter is a VS Code-native extension. All you need:
- Click Install button in [Multimeter VS Code Extension](https://marketplace.visualstudio.com/items?itemName=mshobeyri.multimeter)
- Open **Get Started** from the `Activity bar` and follow the instructions

There you run a POST request as follows:

```yaml
type: api
title: Simple POST
url: https://test.mmt.dev/echo
method: post
format: json
body:
  message: hello
```

That's enough.

- No suites.
- No mocks.
- No workflows.
- No complexity.


## 🧪 Need tests?

```yaml
type: test
steps:
  - http: https://test.mmt.dev/echo
    method: get
    expect:
      status: 200
```

- Still simple.
- Still Git-native.
- Still easy to review.


## 🚀 Scale without switching tools

As your project grows, Multimeter grows with it.

Add:

- Test suites
- Mock servers
- Documentation
- Workflow execution
- Structured reporting
- CI artifacts

**Only when you need them.**

Everything stays in the same ecosystem.

[See all examples →](./examples)


## 🤖 MCP, AI generation, and AI judges

Cursor, Copilot, and Claude write and run the same `.mmt` files you edit in VS Code. MCP (`mmt-mcp`) gives them `scaffold_test`, `validate`, `format`, and `run` — generate tests from an API or a description, then keep them in Git.

**Judge** an API answer in the same test. Compare semantic similarity to an expected reply, or check something open-ended — for example, how funny the response is. Bring your own model (Ollama or cloud). An alternative to a separate Promptfoo eval stack.

See [MCP docs](https://mmt.dev/docs/features/mcp) · [Judge docs](https://mmt.dev/docs/files/judge)


## 🔁 Built for reliable CI

Multimeter validates test definitions before execution.

That means:

- ✅ Earlier feedback
- ✅ More deterministic execution
- ✅ Fewer surprises in CI
- ✅ Easier debugging
- ✅ Reproducible results

GitHub Actions:

```yaml
- uses: actions/checkout@v6
- uses: mshobeyri/testlight-action@v1
  with:
    file: tests/suite.mmt
    report: junit
    report-file: results/junit.xml
```

Or from a terminal using the Multimeter CLI called `testlight`. 

```sh
npm install -g mmt-testlight
testlight run tests/suite.mmt
```

See the [GitHub Action](https://github.com/mshobeyri/testlight-action) and [Testlight install](https://mmt.dev/docs/features/testlight/install).


## 📦 Everything stays in Git

Your code, tests, mocks, documentation, reports, and environment settings live in the same repository.

- ✅ Version controlled
- ✅ Code and tests evolve together
- ✅ Reviewable through pull requests
- ✅ Easy to move and share
- ✅ No platform lock-in
- ✅ AI can update code and tests together
- ✅ Environment variables never go missing
- ✅ Historical test results stay with the project


## 🧠 Philosophy

Most API tools focus on requests.

Multimeter focuses on behavior.

Instead of asking:

> "Did this request return the expected response?"

Multimeter helps you answer:

> "Does this system still behave correctly?"

---

## License

Multimeter is licensed under the [Apache License 2.0](LICENSE.md).

[Demos](https://mmt.dev/demos) · [Documentation](./docs/toc.md) · [Website](https://mmt.dev) · [GitHub](https://github.com/mshobeyri/multimeter)